Chemokines CCL21 and its receptor CCR7 expression in thyroid of thyroiditis in NOD mice induced by iodine excess and thyroglobulin immunization / 中华地方病学杂志

ABSTRACT

Objective Through detecting the expression of chemokine CCL21 and its receptor CCR7 in thyroiditis of NOD mice induced by excessive iodine and thyroglobulin (Tg) immunization,to explore the mechanism of lymphocytic infiltration.Methods Seven to eight weeks old female NOD (non-obese diabetic) mice were used,the mice were divided into four groups by random number table,7 mice for each group.Control groupintoke distilled water;,Tg groupintoke'distilled water,use pig Tg emulsified in Freund's complete adjuvant subcutaneous injection to immunization,0.10 mg Tg for each mouse at 8 weeks old,strengthened immunity at 11 and 15 weeks old (0.05 mg Tg for each mouse,and emulsified by Freund's incomplete adjuvant); iodine excess (HI) groupintoke 0.05％ NaI water; iodine excess combined with Tg (HI + Tg) groupintoke 0.05％ NaI water,Tg immunization method was same to Tg group; all mice were raised in specific pathogen free (SPF) environment.All mice were executed at 16 weeks old,and removed the thyroid tissue.Morphologic change in thyroid was observed by HE staining.Immunofluorescence (IF) staining was used to observe CD3,CD22,CCL21 and CCR7 expression in thyroid.Real-time PCR was used to detect CCL21 mRNA expression in thyroid.Results The morphologic change of thyroid was observed under the light microscope,in HI group,thyroid follicle distended,colloid accumulation,lymphocytes accumulate together and disorganization was seen; Tg group thyroid had scatted lymphocytes; HI + Tg group enhanced inflammation response and disorganization.IF staining showed that lymphocytes infiltrated in thyroid were almost CD3+ T cells,only few scatted CD22+ B cells; CCL21 and CCR7 were negative in control group,CCR7 positive cells were scatted in Tg group but no CCL21 expression,in HI and HI + Tg groups,we could see CCL21 strong positive expression in inflammation area and also had CCR7 positive cells there.CCL21 mRNA relative expression in thyroidTg group (3.20 ± 0.18),HI group (1.72 ± 0.31),and HI ± Tg group (9.94 ± 0.32) increased compared to control group (1.00 ± 0.17,all P ＜ 0.01).Conclusion CCL21 and its receptor CCR7 have improved lymphocytic infiltration in autoimmune thyroiditis